The present disclosure relates generally to systems and methods for operating one or more flight control surfaces of an aircraft (e.g., aircraft flaps).
Aircraft may include different control surfaces, such as lift control surfaces or pitch control surfaces that facilitate controlling movement of the aircraft. Current primary control surfaces are driven by hydraulic actuators that handle hardover events or failures by additional redundancy or valving internal to the actuators. For example, a hardover failure may include the erroneous switching of a system to full command (i.e. full force). When this occurs in relation to the aircraft's elevator surfaces, control is lost and the surfaces are free to move, which if unchecked, can cause problems navigating the aircraft. A hardover failure of a hydraulically-powered aircraft control surface may result, for example, from a jam of the control valve spool or of the valve input arm.
Currently, for example, multiple surfaces, override valve spool sleeves and multiple single actuators may be employed to compensate for and to prevent hardover failures. Such approaches either fail to protect against valve arm jams or rely on all-active systems. Further, this additional redundancy or valving adds costs and complexity, as well as bulk, to the overall control system and, thus, the aircraft. For example, configuration cost and weight may increase, resulting in an increase in both fuel and maintenance costs.